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TPS65982 15V Current limit issue

Andrew Park1
Prodigy 460 points
Other Parts Discussed in Thread: TPS65982, TPS6598X-CONFIG

Team,

I have configured PDOs to support 40W system. as below. ( I have attached pjt file and images as well)

40W_BILLBOARDING_32UD.zip

after I set 2.67A for 15V PDO, I was able to see about 3.5A current limit on the board. can you check whether it is well configured?

Thanks,

Andrew

  • 0
    TI__Prodigy 460 points
    Team,

    do we have any feedback for this?
    I'm still waiting for the response.

    Thanks,
    Andrew
  • 0 in reply to Andrew Park1
    TI__Expert 6505 points
    HI Andrew,

    I see the VBUS drops to zero when the current is 3.5A (OCP may be hit) and then restart again. Are you issuing any 'Gaid' command to TPS65982 when this happens? Do you see this behavior with latest TPS65982 Application Customization tool tool too?

    Regards,
    Arun
  • 0 in reply to Arun Menon
    TI__Prodigy 460 points

    Hi Arun, 

    I have tested with latest tool V2.8. 

    the OCP occurs about 3.25A. and I set the value 2.67 as a maximum current. 

    which current limit setting is applied on the table below? I have attached the pjt file from tool V2.8 as well.08162016_40W_BILLBOARDING_32UD_20V.pjt 

  • 0 in reply to Andrew Park1
    TI__Expert 6505 points
    Hi Andrew,

    The code for setting the OCP limit sets as per the ILIMPPHV table you have pointed out. Since you have two PDOs using the PP_HV, it will take the maximum of the 'Maximum current' settings in it. So since PDO 2 has a 'Maximum current' setting for 3A and PDO3 has a maximum current setting for 2.67A, the PP_HV Switch would select the setting 9 instead of setting 7. That is why you see OCP hitting at 3.55A since setting 9 has the Min, Typ and Max values of 3.02A, 3.355A and 3.691A respectively.

    Can you set the PDO2 Maximume current to 2.67A and check again?

    Btw which firmware version are you using for this?

    Regards,
    Arun
  • 0 in reply to Arun Menon
    TI__Prodigy 460 points

    Arun,

    I have used 1.11.02 base FW version.

    I'll test with 2.67 for both and get back to you.

    can we improve the different current limit settings for the different PDO?

    Thanks,

    Andrew

  • 0 in reply to Arun Menon
    TI__Prodigy 460 points

    Hi Arun,

    How the current limit setting is selected then?

    The way I understand is that 'Current setting min value should be higher than PDO current. Among satisfied settings, the lowest value setting is chosen'

    If I were wrong, please let me know how the current limit setting # is chosen

    And a inquiry about OVP

    OVP is can be selected through OVP trip point

    Is there any scenario than OVP trip point can be changed due to PDO setting?(PDO voltage level)

    Of OVP is fixed?

    Thank you

  • 0 in reply to Hayden Shin
    TI__Mastermind 30280 points
    • Yes, your understanding of Over-Current Protection (OCP) automatic selection is correct
    • Over-Voltage Protection (OVP) canbe automatically relative to VBUS+x% for the valid Type-C connection or PD contract
      • OVP Usage = 00b = OVP Disabled when OVP Trip Point = 0x00, manual setting used for OVP Trip Point = 0x01-0x3F
      • OVP Usage = 01b = VBUS+5%
      • OVP Usage = 10b = VBUS+10%
      • OVPUsage = 11b = VBUS+15%
      • NOTE: At BOOT in Dead Battery, OVP is tripped at 6 Volts because the Type-C connection must be 5V

    The OVP Trip Point (Reg. 0x28, bits 21..16) field in the TPS6598X-CONFIG Tool is described on page 23 of the TPS65982 Host Interface Technical Reference Manual () is a manual way to get more granularity than the automatic OVP Usage field (Reg. 0x28, bits 23:22):

    • OVP Trip Point (min) = 1 * 0.32V + 3.84V = 4.16V (000001b = 0x01 = 1d) 
    • OVP Trip Point (max) = 63 * 0.32V + 3.84V = 24V (111111b = 0x3F = 63d)